As part of an on-going program of study of the physicochemical properties of interacting macromolecules in solution, it is proposed to (a) continue our CD and microtubule-reassembly experiments on the interaction of chlorpromazine and trifluoperazine with mouse brain tubulin and to extend these studies to include other phenothiazines in order to gain insight into the molecular mechanism of action of these tranquilizing drugs; (b) continue our CD and NMR investigation of the solution conformation of bradykinin, Lys-Lys-Lys and model compounds; (c) extend our theoretical calculations on the isoelectric focusing of interacting systems to include the set of reactions, P plus L yields (reversibly) PL and PL plus L yields (reversibly) PL2, where P is a protein and L a small ligand molecule; (d) investigate the interaction of technically important, small organic molecules such as Ampholine with proteins and t-RNA; and (e) initiate a CD study of the solution conformation of Substance P.